What is a Christian? In a dictionary, the definition is simply
N [kris-chuh n] : of, pertaining to, believing in, or belonging to the religion based on the teachings of Jesus Christ
Now to clear things up, "Mormons" is just a term used for the LDS church, which is really called The Church of JESUS CHRIST of Latter Day Saints. Now please correct me if I'm wrong... but they have Jesus Christ IN THE NAME! Clearly they support and believe his teachings... So that includes them in Christianity, as well as Catholics as well as many other religions.

Since my opponent has not provided a new argument, I will make my case and address my opponent’s initial preamble.

Negative Case

Overview:

There are central tenants in which these different religions have differing views on, therefore Mormonism cannot be Christianity [2].

P1: There are core beliefs to Christianity

It is widely accepted that there are core teachings to religions. For example, there is no brand of Christianity that would view Jesus as an ordinary person, despite all the denominations. It is a reasonable premise to work from: assume that there are core teachings to every faith that make them distinct from other religions.

A1: Mormonism disagree with Christianity on the nature of God

A central tenant to Christianity is that there is only one God in all existence (Exodus 20:1-4; Isaiah 43:10; 44:6 and 8; 45:5).

In contrast, Mormonism views God as one of countless gods, that he was a man who once existed on another planet, and then became a god. The Bible further conflicts with this idea, in Pasalm 90:2, saying that God has been God for all eternity. The Bible also rejects the idea of there being multiple Gods. Clearly, Mormonism and Christianity are in direct conflict, on this very important point (who is God).

Furthermore, Mormons, are polytheists, because they believe not only that God was not always God, but that the Holy Spirit, Jesus and God are separate entities: “the Father, the Son and the Holy Ghost are separate and distinct personages” [3].

A2: Mormonism says that Jesus’ Sacrifice is not enough

Mormonism teaches that forgiveness of sins is reached via a cooperative partnership with God. In Articles of Faith, James Talmage, a Latter-Day-Saint apostle, said that, “the sectarian dogma of justification by faith alone has exercised an influence for evil…hence the justifce of the scriptural doctrine that salcation comes to the individual only through obedience” [1, pages 434 and 81].

Comparatively, Christianity views belief in Jesus’ Sacrifice as the only requirement for salvation (Rom. 3:28; 4:1-5). Again, the two faiths are shown to contradict on a very important point.

Rebuttals

My opponent essentially appeals to the name only: The Church of Jesus Christ of Latter Day Saints. It is wholly possible that: an organisation can have a name that does not relate wholly to its function. For example, it is possible that a group of dogs could be called ‘the group of scholarly scholars’, when it is of reality that this dog group in question does not include dogs whom are scholarly scholars. Another example: a touch-football team could be called ‘The Losers’, yet in winning a game, this name would contradict reality.

So, my point is that name does not necessarily reflect reality, as I have not only demonstrated in theory, but also with my negative case. To further add problems for my opponent’s argument, there have yet to be arguments affirming that “Mormons are Christians”, so thus far, there is not only no reason to believe that the resolution is not confirmed despite my opponent’s preamble, but I have gone beyond the call of my burden of proof to show why Mormons are not Christians.

Depends on your definition of "Christian." To me the term is very subjective and basically useless in defining one's faith concerning God and Christ. If you mean to say "biblical" Christians, then no, Mormons are definitely not Christian's and they certainly do not worship the God of the Bible.